Induction synchronous motor



Feb. 26 1924.

' 1,485,006 'r. YAMAMOTO I NDUGT I ON SYNC'HRONOUS MOTOR Filed March 2. 1923 Patented Feb. 26, 1924. I

TADAOKI YAMAIOTO, OF TOKYO,

mnuc'rron srncnaonous moron.

Application fled amt, 1923. Serial in. 022,392.

I To an whom it concern Be it known that I, Tamoxr Ymmoro, subject of the Em ror of Japan, resid' at 1421 Takatai akata-mach1, county 0 Kitatoyoshima refecture of Tokyo, Japan, have inven certain new and useful Improvements in Induction S chronous Motors; and I do declare t e following to be a clear, full, and exact description of the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

In the revious application of T. Yamamoto and M. Kawarada, Serial Number 570,305, dated June 23rd, 1922, an electrical machine was described which comprised in combination an induction -motor, a series gradua previous application. At startingrethe secondary current, being of a higher the speed 'quency grafiually diminishes, more and more generator connected in cascade therewith, a reactor of high inductance, a bi h resistance squirrel cage winding, the sai motor and the said generator being mechanically directly connected.

In this machine, as was fully'explained in the specification, the squirrel cage winding and the seconda selective manner in that at starting it is the former that acts primarily, while it is the latter that. acts primarily at a high 8 d which is, however, lower than the sync ronous speed. This action is' caused by the decrease of frequency in the seconda circuits. 1

n this invention, the hi h resistanoesecondary circuit, instead of being rovided as a squirrel-cage winding electrica l independent of the secondary phase win ing, is provided as a shunt to the reactor connected to the said secondaryphase winding. The

manner ofoperation is exactly the same as that of the machine described in the said uency, will mainly pass through the high resistance provided in shunt to the high inductance, thus producing a high starting torque. As

up and the secondary frecurrent will-flow through the said inductance and consequently throu h the series machine connected in cascade t erewith, and the seriesmachine will finally be excited to generate a current, supplyin an exciting current to the secondary win ing of the inductance motor, synchronizing the aggregate automatically.

phase winding act in a If desired, a squirrel cage winding also may provided on the secondary core. By so doing the torque speedcurve of the aggregate can be regulated as the case may re quire. For example, the starting torque may be made greater than the full load torque.

In the annexed drawing is illustrated one form of the invention.

Referring now more particularly to the characters of reference on the drawing, P de s1 ates a primary winding S a secondary win ing of t e induction motor. When the secondary winding S is provided on the rotor of the induction motor, its terminals are led out through suitably provided slipr ngs and connected with the high inductancesw, c 40, and the high'resistances R R R each of the said high inductances being connected-in parallel to one of the said high resistances. .To one of the said inductances, for example '00,, is connected in series therewith a series commutator generator comprisin winding F. his generator is preferably connected mechanically directly to the said induction motor. 1

In an aggregate formed in this manner if an alternating current is supplied to it on the induction motor side, the aggregate will start as an ordinary induction motor. At starting as well as while the speed is low, the secondary frequency, being com arable with the primary frequency, ls stil high, therefore, the secondary current will mainl pass through the resistances R-,, R,, R,, an the starting torque of the motor will be large. As the aggregate gains in speed and the secondary frequency gradually diminishes, more and more current will flow anarmature A and a field through the inductances a a;,, at, and the series machine then through the resistances in parallel to them. When the secondary frequency goes down to a certain sufiiciently All of this has been fully ex lained in the I said previous application of Kawarada.

The neutral of resi tances point 2 formed by the set of mductances amamoto and oint O formed b the set ?R y and the neutral .1 m as, may either be electrically connected to each other or insulated one from the other. When these two points are connected to each other, as shown in the figure, the regulation of the exciting current, after the above mentioned synchronization is attained, may be effected by varyin the resistance R, which is in parallel wit the series generator. On the other hand, when the two neutral points are insulated one from the other, the regulation of the exciting current ma be carried out b means of the resistance and the parallel connected resistances R and R By providin a high resistance squirrel cage winding TC on the secondary core of the induction machine in addition to the phase winding S, an effect equivalent to the triple secondary winding may be obtained,

that is to say, any desired shape maybe given to the speed-torque characteristic of the aggregate. For example, it will be possible to produce a machine whose starting torque is greater than the normal full load torque.

As desired, instead of inserting the field winding F of the series machine in one of the phases as shown in the figure, it may be uniformly distributed into all the secondary phases as in the said previous application.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed I declare that what I claim is 1. An alternating current motor comprising in combination an induction machine, a series wound machine connected mechanically to the said induction machine, a reactor of high inductance in the secondar circuit of the said induction machine, a hi I resistance in parallel to the said reactor, t e said series wound machine bein connected in series with the said reactor hut in parallel to the said high resistance.

2. An alternating current motor comprising in combination an induction machine, a series wound, machine connected mechanically to the said induction machine, areactor of high inductance in the secondar circuit of the said induction machine, a bi h adjustable resistance in parallel to the said reactor, the series wound machine being connected in series with the said reactor but in parallel to the said high resistance.

3. An alternating current motor comprising in combination an induction machine provided with a high resistance squirrel cage winding, a series wound machine connected mechanically to the said induction machine, a reactor of high inductance in the secondary circuit of the said induction machine, a high adjustable resistance in parallel to the said reactor, the said series wound machine being connected in series with the said reactor but in parallel to the said high resistance.

In witness whereof, I have hereunto signed my name inthe presence of two subscribing witnesses.

TADAOKI YAMAMOTO.

Witnesses Hmno Kn,

HIROSADA Ornm. 

